The overall objective of this research is to determine whether human male sexual behavior is influenced through an olfactory pheromone (external chemical messenger) effective in Rhesus monkeys and present in human female vaginal secretions. It is hypothesized that if the pheromone affects male behavior, the probability of male desire, intercourse and orgasm will be higher following exposure to pheromone than following exposure to placebo or control materials. The methodology of this study provides for exposure to a synthetic pheromone applied by the wife as a perfume, alternating in a random sequency with placebo and control materials. To participate, couples must be married, living together, and contracepting by some means other than oral agents or rhythm method. Daily reports of sexual behavior and wife's basal body temperature are collected.